ZS-001 / REV. 0220-05

20-05
Lowley's Line Tracking Car

Overview

An autonomous line-following vehicle combining a laser-cut apple-shaped chassis, four infrared sensors and Arduino-based motor control.

Apple-shaped line-tracking vehicle
FIGURE 01 — Apple-shaped line-tracking vehicle

Objective

Our goal was to design a two wheeled autonomous vehicle capable of reliably following a white tape line using four infrared reflectance sensors. The system needed to combine mechanical design, sensor placement, and control logic into a compact, stable, and visually distinctive robot. We also wanted to create a playful, story driven aesthetic, hence the apple shaped chassis inspired by Lowly Worm’s car.

Engineering constraints

A two-wheeled autonomous vehicle following white tape using four infrared reflectance sensors, with a compact, stable, apple-shaped chassis.

My contributions

I was responsible for most of the mechanical design and fabrication, including:

The Laser Cut Chassis base which includes cutouts for the motor mounts, sensor hardware, rear caster wheel, wire routing holes, and press-fit slots for the laser-cut side panels.
FIGURE 02 — The Laser Cut Chassis base which includes cutouts for the motor mounts, sensor hardware, rear caster wheel, wire routing holes, and press-fit slots for the laser-cut side panels.
Final Laser cut piece. There are two mirrored side panels but the right hand side is partially important as this is where the powered source and the Arduino usb-c is plugged in. That is, it took “bites” out of the apple in order to allow the necessary electrical while maintaining aesthetics.
FIGURE 03 — Final Laser cut piece. There are two mirrored side panels but the right hand side is partially important as this is where the powered source and the Arduino usb-c is plugged in. That is, it took “bites” out of the apple in order to allow the necessary electrical while maintaining aesthetics.

Design and fabrication process

Electronics & Control

We implemented a closed loop control system using:

Sensor values were thresholded and fed into simple state logic that adjusted motor speeds in real time. The outer pair of sensors helped with wide turns and course recovery, while the inner pair ensured precise line tracking. A serial interface allowed live tuning of speed and threshold parameters during testing.

Results

Over-head view of the car
FIGURE 04 — Over-head view of the car

After sensor calibration and parameter tuning, the Apple Car successfully completed the official course with a best lap time of 36 seconds. It demonstrated stable, consistent tracking under varying lighting conditions and reliably re-acquired the line after overshoot.

The combination of a playful mechanical design, a lightweight laser cut structure, and robust closed loop control produced a robot that was both functional and visually charming. The serial tunable motor control allowed quick adjustments during testing, which helped refine the robot’s behavior efficiently.

Overall, the project blended creative design with integrated electronics, resulting in a polished, expressive, and fully autonomous line following vehicle.


video of the car in action! apple1.mov - Google Drive

Skills and tools

OnShape, Laser Cutter, Adobe Illustrator, Integration

OCT 202620-05